Scheduling Wireless Communication Among Delay-Sensitive and Delay-Insensitive Terminals

1. A scheduling method by a point coordinator (PC) of a wireless communication system including a plurality of terminals and the PC for providing a network access service to the terminals, the scheduling method comprising the steps of: classifying the terminals into delay-sensitive terminals and delay-insensitive terminals according to their traffic types; setting an initial value and a maximum value of a poll failure counter of each of the delay-sensitive terminals; polling each of the delay-sensitive terminals; determining whether there exists a delay-sensitive terminal of which a present value of the poll failure counter is less than the maximum value; and if there exists no delay-sensitive terminal of which the present value of the poll failure counter is less than the maximum value, sequentially polling the delay-sensitive terminals and the delay-insensitive terminals, if the present value is less than the maximum value at any of the delay-sensitive terminals, the polling of each of the delay-sensitive terminals comprises: transmitting a polling packet to each delay-sensitive terminal where the present value is less than the maximum value; determining whether a response packet responsive to the polling packet is received from the delay-sensitive terminal; if the response packet is received, initializing the poll failure counter of the delay-sensitive terminal to 0; and if the response packet is not received, increasing the poll failure counter of the delay-sensitive terminal by 1.

2. The scheduling method of claim 1 , wherein the setting the initial value and a maximum value of a poll failure counter of each of the delay-sensitive terminals includes setting the initial value of the poll failure counter to 0.

3. The scheduling method of claim 1 , further comprising: resetting the poll failure counters of the delay-sensitive terminals to 0 after the sequential polling of the delay-sensitive terminals and the delay-insensitive terminals; and returning to the step of polling each of the delay-sensitive terminals.

4. A scheduling method by a point coordinator (PC) of a wireless communication system including a plurality of terminals and the PC for providing a network access service to the terminals, the scheduling method comprising the steps of: classifying the terminals into delay-sensitive terminals and delay-insensitive terminals according to their traffic types; setting an initial value and a maximum value of a poll failure counter of each of the delay-sensitive terminals; determining whether a present value of the poll failure counter of each of the delay-sensitive terminals is less than the maximum value; if the present value is less than the maximum value at any of the delay sensitive terminals, transmitting a polling packet to each delay-sensitive terminal where the present value is less than the maximum value; determining whether a response packet responsive to the polling packet is received from the delay-sensitive terminal; if the response packet is received, initializing the poll failure counter of the delay-sensitive terminal to 0; if the response packet is not received, increasing the poll failure counter of the delay-sensitive terminal by 1; determining whether there exists a delay-sensitive terminal of which a present value of the poll failure counter is less than the maximum value; if there exists no delay-sensitive terminal of which the present value of the poll failure counter is less than the maximum value, sequentially polling the delay-sensitive terminals and the delay-insensitive terminals; resetting the poll failure counters of the delay-sensitive terminals to 0 after the sequential polling of the delay-sensitive terminals and the delay-insensitive terminals; and returning to the step of polling each of the delay-sensitive terminals.

5. A system for scheduling wireless communication, comprising: at least one delay-sensitive terminal; at least one delay-insensitive terminal; and a points coordinator (PC), wherein the PC is configured to poll each of the at least one delay sensitive terminals, and, in response to none of the at least one delay sensitive terminals having a value of a poll failure counter that is less than a predetermined maximum value, the PC is further configured to sequentially poll the at least one delay sensitive terminal and the at least one delay insensitive terminal, wherein the PC is configured to determine whether a current value of the poll failure counter of each of the at least one delay-sensitive terminals is less than the predetermined maximum value, transmit a polling packet to each delay-sensitive terminal where the current value is less than the predetermined maximum value, determine whether a response packet responsive to the polling packet is received from one of the delay-sensitive terminals where the current value is less than the predetermined maximum value, initialize the poll failure counter of the delay-sensitive terminal where the current value is less than the predetermined maximum value to 0 if the response packet is received, and increase the poll failure counter of the delay-sensitive terminal where the current value is less than the predetermined maximum value by 1 if the response packet is not received.